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Subject: Re: [OMPI devel] Gather(linear_sync) is truncated using derived data type
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2012-01-26 17:43:49


Oops -- somehow we missed this email. Thanks for the bug report!

I've filed https://svn.open-mpi.org/trac/ompi/ticket/2981 for it.

On Jan 16, 2012, at 12:36 AM, Y.MATSUMOTO wrote:

> Dear All,
>
> Next feed back is about MPI_Gather problem.
>
> Gather may be truncated in following condition:
> 1:ompi_coll_tuned_gather_intra_linear_sync is called.
> (message size is over 6000B)
>
> 2:Either send data type or recv data type is derived type and
> other data type is predefined data type.
>
> Truncated is occurred by attached C file(following output).
>
> Output:
> *** An error occurred in MPI_Gather
> *** on communicator MPI_COMM_WORLD
> *** MPI_ERR_TRUNCATE: message truncated
> *** MPI_ERRORS_ARE_FATAL (your MPI job will now abort)
>
> In this C program,
> "first_segment_count(variable in ompi_coll_tuned_gather_intra_linear_sync)" is
> different between root and non-root.
> That makes messages truncated.
> "first_segment_size" can not be dividable by derived data type's size,
> but can dividable by predefined data type's size.
> But we don't solve this problem.
> So, we don't choose linear_sync in coll_tuned_decision_fixed.c.
>
> Best Regards,
>
> Yuki MATSUMOTO
> MPI development team,
> Fujitsu
>
> <gather.c>_______________________________________________
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-- 
Jeff Squyres
jsquyres_at_[hidden]
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